Herbicide Tank Mix Calculator

Convert any herbicide label rate — oz/acre, oz/gallon, oz/1,000 sq ft, or a 1:X dilution — into how many fluid ounces to pour into your tank, plus oz/gal, coverage, and tanks needed.

What the label says

Label rate unit

oz / acre oz / gal oz / 1,000 sq ft 1:X ratio

Label rate

Fluid ounces per acre, from the label (e.g. 32).

Your sprayer & tank

Carrier rate (GPA)

Gallons of spray your sprayer applies per acre. Not on the label — it's your sprayer's calibration. Need it? See the Sprayer Calibration Calculator, or catch 1 nozzle's output over a 340 sq ft (17×20 ft) plot — ounces caught ≈ GPA.

Tank / mix volume

gal L

Tank / mix volume value

Your sprayer tank or batch size.

Area to treat (optional)

Area

sq ft acres

Area value

Leave blank to skip 'tanks needed'.

Concentrate to add to this tank

—

Enter your label rate, pick its unit, and your tank size.

Concentration oz of concentrate per gallon of mix: —
Acres this tank covers: —
Water / carrier volume: —
Tanks needed for the area: —
Total concentrate for the area: —

Export

Reference only — verify against the product label; not a compliance record.

How this is calculated

The whole calculator rests on one identity — your label rate crossed with your carrier rate (GPA) gives the per-gallon concentration, which then scales to your tank and your area.

Branch A (oz/acre):   oz/gal = labelRate ÷ GPA
Branch B (oz/gal):    oz/gal = labelRate                (identity)
Branch C (oz/1000):   oz/acre = labelRate × 43.56
                      oz/gal  = oz/acre ÷ GPA
Branch D (1:X ratio): oz/gal = 128 ÷ (1 + X)

shared (all branches):
  oz to add this tank = oz/gal × tankGal
  water / carrier gal = tankGal − (oz to add ÷ 128)

coverage (per-area branches):
  acres this tank covers = tankGal ÷ GPA
  tanks needed           = ceil(area acres ÷ acres-per-tank)   (round UP)

Worked example: a 32 oz/acre label, a sprayer calibrated to 20 GPA, and a 100-gal tank → 32 ÷ 20 = 1.60 oz/gal × 100 gal = 160 fl oz of concentrate, covering 100 ÷ 20 = 5.00 acres, with about 98.75 gal of water.

The 43.56 constant is 43,560 sq ft per acre ÷ 1,000. The 128 constant is fluid ounces per US gallon. The GPA field is your sprayer's calibration — it is not printed on the label; the 1/128th method (catch one nozzle's output over a 340 sq ft plot — the ounces caught ≈ GPA) is the quickest way to find it. Tanks needed always rounds up: rounding down leaves coverage short.

Sources: Ohio State Extension FABE-530 (calibration & sprayer math; acres-per-tank method), Tennessee PSEP (common pesticide calculations), and Pesticide Environmental Stewardship (the 1/128th ounces-to-gallons method). Secondary cups / tbsp / mL measures are display helpers (1 cup = 8 fl oz, 1 tbsp = 0.5 fl oz, 1 fl oz = 29.5735 mL).

Sources

Calibration & Math for Sprayer Application (FABE-530). Ohio State University Extension. Retrieved Jun 20, 2026.
Common Pesticide Calculations. University of Tennessee PSEP. Retrieved Jun 20, 2026.
Ounces-to-Gallons (1/128th) Calibration Method. Pesticide Environmental Stewardship. Retrieved Jun 20, 2026.

How we choose and check our formulas